pebble

A Pebble smart watch, and a Raspberry Pi. They are a perfect match. This is probably what [Daniel] thought when he embarked upon his latest project, a smart doorbell called the PebblyPi (tip submitted by [Ben]).

The actual project is quite easy to implement. All you need really need is a Raspberry Pi, a switch, a resistor, and a Pebble Smart Watch (plus a smart phone). Using a simple Python script on the Raspberry Pi, button press notifications are sent to Pushover, which allows the notification to arrive on your smart phone (and thus your Pebble Smart Watch). Pushover is a very cool notification service for Android devices, iPhones, iPads, and your Desktop. The concept behind this project is great, and the fact that it is so simple to implement opens up many other possibilities for interfacing your home electronics with the Pebble Smart Watch (or even just your smart phone). The ability to create custom notifications on any of your devices using any internet connected system is amazing!

[Colt] found himself with a broken Pebble, so he fixed it. The Pebble watch really ignited the smartwatch world with its record-breaking Kickstarter campaign. Working on the Pebble has proved to be frustrating experience for hardware hackers though. Ifixit’s teardown revealed the Pebble extremely difficult to repair. This isn’t due to some evil plan by the smartwatch gods to keep us from repairing our toys. It’s a problem that comes from stuffing a lot electronics into a small waterproof package. [Colt’s] problem was a bad screen. Pebble has a few known screen issues with their early models. Blinking screens, snow, and outright failed screens seemed to happen at an alarming rate as the early Kickstarter editions landed. Thankfully all those issues were corrected and replacements sent to the unlucky owners.

The actual screen used in the Pebble is a Sharp Memory LCD. Memory is an apt name as the screens actually behave as a SPI attached write only memory. Sharp sells flexible printed circuit (FPC) versions of the LCDs to aid in debugging. For space constrained designs though, an elastomeric or “zebra strip” connector is the common way to go. Alternating bands of conductive and insulating material make electrical connections between the Pebble’s circuit board and the conductive portions of the LCD glass.

[Colt] found himself with a dead screen out of warranty, so he decided to attempt a screen replacement. He found a replacement screen from Mouser, and proceeded to remove the top case of his watch. The top plastic case seems to be the hardest part of getting into a Pebble. It appears to be bonded with a glue that is stronger than the plastic itself. [Colt] broke the glass of his screen during the removal, which wasn’t a big deal as it was already dead. Prying only destroyed the top plastic, so he broke out a rotary tool which made quick work of the plastic. The new screen worked perfectly, but had to be held in just the right position over its zebra connector. Some waterproof epoxy held it in place permanently. The next step was a new top cover. An old flip phone donated its plastic shell to the effort, and hot glue kept everything in place. [Colt] finished his work with a couple of layers of model paint. The result certainly isn’t as pretty or waterproof as the original. It is functional though, and about $120 USD cheaper than buying a new Pebble.

So far the two bits of hardware used in his experiments are shown in the image above. The watch itself serves as the controller, interacting with the Ethernet relay board seen in the background. The watch communicates via Bluetooth but you don’t have to know much about that thanks to the example files available from the repository. With communications taken care of he needed a menu system to access commands on the watch. Instead of coding his own he hacked a playlist into the built-in music menu. This allows him to switch the relays on and off again as if he were playing or pausing audio tracks. See it in action after the break.